Atypical Facial Pain Treatment (AFP)
This is also termed atypical facial neuralgia, chronic idiopathic facial pain,or psychogenic facial pain), is a type of chronic facial pain which does not fulfill any other diagnosis. There is no consensus as to a globally accepted definition, and there is even controversy as to whether the term should be continued to be used. Both the International Headache Society (IHS) and the International Association for the Study of Pain (IASP) have adopted the term persistent idiopathic facial pain (PIFP) to replace AFP.
In the 2nd Edition of the International Classification of Headache Disorders (ICHD-2), PIFP is defined as "persistent facial pain that does not have the characteristics of the cranial neuralgias and is not attributed to another disorder. However, the term AFP continues to be used by the World Health Organization's 10th revision of the International Statistical Classification of Diseases and Related Health Problems and remains in general use by clinicians to refer to chronic facial pain that does not meet any diagnostic criteria and does not respond to most treatments.
The main features of AFP are: no objective signs, negative results with all investigations/ tests, no obvious explanation for the cause of the pain, and a poor response to attempted treatments.
AFP has been described variably as a medically unexplained symptom, a diagnosis of exclusion, a psychogenic cause of pain (e.g. a manifestation of somatoform disorder), and as a neuropathy.
AFP is usually burning and continuous in nature, and may last for many years. Depression and anxiety are often associated with AFP, which are either described as a contributing cause of the pain, or the emotional consequences of suffering with unrelieved, chronic pain. For unknown reasons, AFP is significantly more common in middle aged or elderly people, and in females.
Atypical odontalgia (AO, also termed phantom tooth pain, psychogenic toothache, or persistent dentoalveolar pain disorder), is very similar in many respects to AFP, with some sources treating them as the same entity, and others describing the former as a sub-type of AFP. Generally, the term AO may be used where the pain is confined to the teeth or gums, and AFP when the pain involves other parts of the face.
As with AFP, there is a similar lack of standardization of terms and no consensus regarding a globally accepted definition surrounding AO. Generally definitions of AO state that it is pain with no demonstrable cause which is perceived to be coming from a tooth or multiple teeth, and is not relived by standard treatments to alleviate dental pain.
Depending upon the exact presentation of atypical facial pain and atypical odontalgia, it could be considered as craniofacial pain or orofacial pain. It has been suggested that, in truth, AFP and AO are umbrella terms for a heterogenous group of misdiagnosed or not yet fully understood conditions, and they are unlikely to each represent a single, discrete condition.
AFP is described as one of the 4 recognizable symptom complexes of chronic facial pain, along with burning mouth syndrome, temporomandibular joint dysfunction (TMD) and atypical odontalgia. However, there is a degree of overlap between the features of these diagnoses, e.g. between AFP and TMD and burning mouth syndrome.
Some sources list some non-specific signs that may be associated with AFP/AO. These include increased temperature and tenderness of the mucosa in the affected area, which is otherwise normal in every regard.
Patient often reports symptoms of paresthesia, pain, and throbbing. Physical examination may be normal, but hypoesthesia, hyperesthesia, and allodynia may be found.
The features of atypical facial pain can be considered according to the Socrates pain assessment method (see table).
|Parameter||Usual findings in atypical facial pain/atypical Odontalgia|
||The pain is often poorly localized, but is usually located in the region of the maxilla (upper jaw), which is affected more than the mandibular region, although sometimes both may be affected. The pains location does not correlate to the anatomic distribution of trigeminal nerve, and may be located unilaterally (more usually) or bilaterally. Sometimes the pain may be seem to be located in a tooth that has been previously extracted, or associated with a previous surgical procedure. Over time the pain may migrate, spontaneously or as a response to interventions, to other sites, or slowly expand. Where the teeth are involved, usually a whole quadrant is affected.
||Usually present continuously for months or years, with intermittent periods of increased pain, and an overall gradual increase in pain over time. Sometimes the onset may be mistakenly attributed by the individual to a dental procedure in the past.
||Usually described as dull, aching pain. Sometimes the pain is hard to describe, and affected individuals resort to emotive words to describe the pain. Other descriptions include "gripping", "gnawing", "nagging", "vice-like", "crushing", "burning", "deep" or "pressure".
||The pain may radiate in anatomically impossible ways, e.g. crossing anatomic borders such as dermatomes or the midline. AFP may extend to involve the temple, neck, or occipital region (the back of the head).
||There is a strong association with depression and anxiety. Sometimes other conditions may be associated, such as irritable bowel syndrome, neck pain, back pain, pelvic pain, fibromyalgia, subjective xerostomia (a dry mouth symptom with no identifiable cause), dysgeusia (bad taste), headaches,dysmenorrhea (excessive period pains), Chronic fatigue syndrome, or Dyspepsia.
||Pain is continuous throughout the day, or less commonly may be intermittent.
||No usual precipitating or relieving factors. Notably simple analgesics do not usually relieve the pain and there are no "trigger zones" (as with trigeminal neuralgia). Facial movements also do not usually trigger the pain. Stress can make the pain worse.
||The intensity is variable, but usually described (by clinicians) as moderate to severe, and may be as severe as trigeminal neuralgia (but the pain is of different character, especially with regards AFP usually being continuous rather than the paroxysmal pain seen in trigeminal neuralgia).
|Effect on sleep
||AFP does not usually wake people from sleep.
||Possibly multiple failed attempts at previous medical and/or dental treatment, e.g. tooth extraction. Sometimes a treatment may provide temporary relief, only for the pain to return days or weeks later, or in a different part of the face.
Psychosocial interventions for AFP include cognitive behavioral therapy and biofeedback. A systematic review reported that there was weak evidence to support the use of these treatments to improve long-term outcomes in chronic orofacial pain,however these results were based primarily upon temporomandibular joint dysfunction and burning mouth syndrome rather than ATP and AO.
Psychosocial interventions assume 2 models of chronic facial pain, namely "inactivity" and "over activity". The former is where people with pain become conditioned to avoid physical activity as a result of exacerbating their pain. These negative thoughts and behaviors in fact prolong and intensify their symptoms. Some psychosocial interventions work on this fear-avoidance behaviour to improve functioning and thereby alleviate symptoms. The over activity model involves factors such as anxiety, depression or anger acting to increase pain by triggering autonomic, visceral and skeletal activity.
- Centrally acting muscle relaxants
Some have suggested that surgery is not an appropriate for treatment for AFP, however the frequent failure medical treatment to relieve pain has occasionally lead surgeons to attempt surgical treatments. Surgery may give a temporary remission from pain, but rarely is there a long term cure achieved via these measures. Sometimes the pain may be increased or simply migrate to an adjacent area following a surgical procedure. Descriptions of procedures such as removal of a portion of the affected branch of the trigeminal nerve, or direct injections of a caustic substance (e.g. phenol, glycerol, alcohol) into the nerve have been reported. Proponents of the so-called "Neuralgia inducing cavitational necrosis" suggest surgical exploration of the bone marrow surrounding the intra-bony course of the affected nerve to discover diseased marrow.
It is very important to consult oro-facial pain specialists (trained to treat such problems) for this condition as research suggests that people with AFP are not helped greatly by other health care professionals. One study reported that on average, individuals had consulted 7.5 different doctors. 91% had seen dentists, 80% physicians, 66% neurologists, 63% ear, nose and throat surgeons, 31% orthopedic and maxillofacial surgeons, 23% psychiatrists, 14% neurosurgeons and 6% ophalmologists and dermatologists. In this study, the individuals had been subjected to a wide variety of different treatments, from surgery, antidepressants, analgesics and physical therapies. None of the persons reported that surgery was beneficial, and in many cases the pain was worsened by surgery.